PR16005, avr linker crash on a particular instruction sequence with --relax

PR16005, avr linker crash on a particular instruction sequence with --relax

[Alan Modra]

It's possible for relax_delete_bytes to be called with section
contents NULL, as demonstrated by the testcase in this PR.

	PR 16005
	* elf32-avr.c (elf32_avr_relax_delete_bytes): Get section contents
	if not already available.

diff --git a/bfd/elf32-avr.c b/bfd/elf32-avr.c
index 48591b8c904..3a1d238e707 100644
--- a/bfd/elf32-avr.c
+++ b/bfd/elf32-avr.c
@@ -1927,6 +1927,9 @@ elf32_avr_relax_delete_bytes (bfd *abfd,
   symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
   sec_shndx = _bfd_elf_section_from_bfd_section (abfd, sec);
   contents = elf_section_data (sec)->this_hdr.contents;
+  if (contents == NULL
+      && !bfd_malloc_and_get_section (abfd, sec, &contents))
+    return false;
   relax_info = get_avr_relax_info (sec);
 
   toaddr = sec->size;

-- 
Alan Modra
Australia Development Lab, IBM

Re: PR16005, avr linker crash on a particular instruction sequence with --relax

[Alan Modra]

The last patch wasn't so clever.  The contents in fact have already
been read, just not cached where relax_delete_bytes expects them.
relax_delete_bytes also modifies relocs and syms, so they should be
cached too.

	PR 16005
	* elf32-avr.c (elf32_avr_relax_delete_bytes): Revert last change.
	(elf32_avr_relax_section): Cache contents, relocs and syms
	before calling relax_delete_bytes.

diff --git a/bfd/elf32-avr.c b/bfd/elf32-avr.c
index 3a1d238e707..8c003d0553b 100644
--- a/bfd/elf32-avr.c
+++ b/bfd/elf32-avr.c
@@ -1927,9 +1927,6 @@ elf32_avr_relax_delete_bytes (bfd *abfd,
   symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
   sec_shndx = _bfd_elf_section_from_bfd_section (abfd, sec);
   contents = elf_section_data (sec)->this_hdr.contents;
-  if (contents == NULL
-      && !bfd_malloc_and_get_section (abfd, sec, &contents))
-    return false;
   relax_info = get_avr_relax_info (sec);
 
   toaddr = sec->size;
@@ -3071,6 +3068,10 @@ elf32_avr_relax_section (bfd *abfd,
 				      "at address 0x%x deleted.\n",
 				      (int) dot + insn_size);
 
+			    elf_section_data (sec)->relocs = internal_relocs;
+			    elf_section_data (sec)->this_hdr.contents = contents;
+			    symtab_hdr->contents = (unsigned char *) isymbuf;
+
 			    /* Delete two bytes of data.  */
 			    if (!elf32_avr_relax_delete_bytes (abfd, sec,
 							       irel->r_offset + insn_size, 2,

-- 
Alan Modra
Australia Development Lab, IBM